1. Field of the Invention
The present invention relates to a power supply system and method including a power generator and a storage device, which can form a power transfer path for improving the power supply efficiency.
2. Description of the Prior Art
Among distributed power supplies, a power supply that generates DC power may perform photovoltaic power generation, fuel cell power generation, wind power generation, or the like, and an apparatus that performs reverse conversion of a received DC power into an AC power and supplies the AC power to a system is called a grid-interactive inverter.
That is, the grid-interactive inverter is a power conversion apparatus which converts a DC power supply that can be obtained from solar cells using sunlight that is a representative alternative energy source or fuel cells into an AC power supply using a semiconductor switch device, and supplies the AC-converted power to a predetermined power system.
The grid-interactive inverter has the features that the inverter is of a grid-interactive type, it is required that the DC input voltage has a very wide range, and the output power is always changed. That is, the grid-interactive inverter for the distributed power supply always has a different amount of output power, and it is required for the inverter to generate the power from “0” at a minimum to its own capacity.
Accordingly, the grid-interactive inverter has been developed as a power supply system that is configured to include a storage device which stores a surplus power when the amount of power generation is large and supplies the stored power when the amount of power generation is small.
FIG. 1 is a block diagram illustrating the configuration of a power supply system in the related art. Referring to FIG. 1, the power supply system in the related art includes a power generator 10, a boost converter 20, an inverter 30, a storage device 40, a DC-to-DC (DC/DC) converter 90, a path setting device 80, and a controller 70.
The power generator 10 is a device that generates electrical energy using kinetic energy, optical energy, and the like. Specifically, the power generator 10 is a device that converts energy in the form of kinetic energy, optical energy, or the like, into an electrical energy form.
The storage device 40 is a device that can store the electrical energy, and may be implemented using a battery or an element such as a super conductor.
The boost converter 20 is a device for converting a voltage of the electrical energy that is generated by the power generator into a voltage that is required in the inverter.
The inverter 30 has been described as above, and the detailed description thereof will be omitted.
The DC/DC converter 90 is a device that converts the boost-converted electrical energy so that the electrical energy has a voltage required in the storage device 40.
The path setting device 80 and the controller 70 transfer the boost-converted electrical energy to the inverter 30 when the system 60 requires the power and transfer the boost-converted electrical energy to the DC/DC converter 90 when the system 60 does not require the power. Further, the path setting device 80 and the controller 70 form a path for transferring the electrical energy stored in the storage device 40 to the inverter 30 when the amount of power generation performed by the power generator 10 is insufficient.
For this, the controller 70 receives situational information from the power generator 10, the storage device 40, and the system 60.
However, the power supply system in the related art has the problems that the power is consumed while the converter converts the voltage and the power quality is deteriorated during the power conversion.